The present invention relates to an edge light device for a lighting panel.
FIG. 7 is a perspective view showing a conventional edge light, and FIG. 8 is a sectional view of the edge light.
An edge light 101 comprises a substrate 102 made of glass epoxy resin, terminal electrodes 103 and 104 formed on the substrate 102 at the upper surface, sides and underside, and a light emitting diode 106 mounted on the terminal electrode 103. An anode 106a and cathode 106c are connected to the terminal electrodes 103 and 104 by bonding wires 107, respectively. The light emitting diode (hereinafter called LED) 106 and bonding wires 107 are sealed by a seal 108 made of transmissive resin.
On the surface of the seal 108, a convex lens 108b is formed above the LED 106.
When an electric current is applied to the LED 106 through the terminal electrodes 103 and 104 and bonding wires 107, the LED 106 emits light. Light beams which reach the convex lens 108b are refracted and discharged as light beams S1, and condensed to an annular spot 112 on a lighting panel 111 as shown in FIG. 8a. 
FIG. 9 is a plan view showing another conventional edge light source, FIG. 10 is a sectional view of the edge light, and FIG. 10a is a plan view of a spot.
An edge light 121 comprises a substrate 122 having a recess 126 of a parabola sectional shape. On the other surface of the recess 126, a reflection film 126a is formed. Terminal electrodes 123 and 124 are formed on the substrate 122 at the upper surface, sides and underside. The LED 106 is securely mounted on the substrate 122. The anode 106a and cathode 106c are connected to the terminal electrodes 103 and 104 by bonding wires 107, respectively. The LED 106 and the bonding wires 107 are sealed by a seal 128.
When the LED 106 is operated, parallel light beams S2 are discharged and a spot 132 is formed on a lighting panel 131.
In order to use the edge light for illuminating a lighting panel for a liquid crystal device (LCD), there are following problems.
As described above, each of the edge lights 101 and 121 applies light beams to each lighting panel as a small annular spot. On the other hand, the lighting panel has a laterally elongated long side since the lighting panel has an upper panel surface having a large area for illuminating the LCD. Consequently, only one edge light can not illuminate a whole face of the side of the lighting panel at uniform brightness. Therefore, in order to light uniformly the side, a long edge light having a plurality of light sources must be disposed along the side. As a result, the cost for manufacturing the edge light increases.